Application Real-Time Monitoring Service:User Session Trace

Mobile (iOS and Android)

Session Creation

A new session with a unique Session ID is created when the app:

• Launches for the first time

• Returns to the foreground from the background

Session Continuation

If the app returns to the foreground within 60 seconds of entering the background, the SDK reuses the current session instead of creating a new one.

Session Expiration

If the app remains in the background for more than 60 seconds, the previous session ends. The SDK creates a new session when the app returns to the foreground.

Session Termination

The current session ends when the app is terminated.

┌─────────────┐    ┌──────────────┐    ┌─────────────┐
│  App Launch │───▶│ Create Session│───▶│ Collect Events│
└─────────────┘    └──────────────┘    └──────┬──────┘
                                              │
                          ┌───────────────────┤
                          ▼                   ▼
                   ┌─────────────┐    ┌──────────────┐
                   │ Enter Background│  │ App Terminated│
                   └──────┬──────┘    └──────────────┘
                          │
              ┌───────────┴───────────┐
              ▼                       ▼
     ┌────────────────┐     ┌────────────────┐
     │ Return ≤60s    │     │ Return >60s    │
     │ Reuse Session  │     │ New Session    │
     └────────────────┘     └────────────────┘

Web (Web and Mini Programs)

Session Creation

A new session with a unique Session ID is created when a user first visits the page.

Session Continuation

The session remains active while the user continues interacting with the page (clicks, scrolls, navigation).

Session Expiration

When the user has no interaction for longer than the timeout period, the session ends. A new session is created automatically upon the next interaction.

Session Termination

The current session ends when the user closes the page or browser.

Configure Sampling Rate

Manual Configuration (Web and Mini Programs)

During RUM integration, initialize the sessionConfig function to configure the sampling rate.

armsRum.init({
  endpoint: "your endpoint",
  sessionConfig: {
    sampleRate: 0.5, // 50% sample rate
    maxDuration: 86400000,
    overtime: 3600000,
    storage: 'cookie',
  },
});

Remote Configuration (All Platforms)

1. Log in to the RUM console.

2. Navigate to Application List > Application Details > Application Settings > SDK Configuration.

3. Configure the session sampling rate under Session Configuration.

Note: For Web and Mini Program applications, add the remoteConfig field when initializing the RUM SDK to enable remote session sampling rate configuration. The SDK fetches the remote OSS configuration during initialization and updates the probe configuration accordingly.

armsRum.init({
  endpoint: "your endpoint",
  remoteConfig: {
    enable: true,
    mode: 'remote-first',
  }
});

After the SDK retrieves the remote configuration, it immediately updates the settings and stores the configuration locally. This allows the SDK to use the stored configuration for initialization the next time it starts. Note that the SDK version must be 0.0.37 or later.

Page Load (View)

Records loading and engagement metrics for each page. The SDK captures page lifecycle events automatically without manual instrumentation.

User Action (Action)

Records user interactions such as clicks and scrolls. The SDK automatically intercepts user interaction events.

Resource Request (Resource)

Captures network requests initiated by the application, recording the complete request lifecycle and performance metrics.

Exception and Crash (Error)

Collects application crashes and uncaught exceptions. The SDK also supports manual reporting of custom exceptions through its API. Exception events are automatically correlated with the current session and page context, helping reconstruct the complete user operation path when the exception occurred.

Exception Types

• Application Crashes

  • Mobile: Runtime uncaught exceptions and system signal exceptions (SIGSEGV, SIGABRT), reported automatically on next launch

  • Web: JavaScript errors and unhandled Promise rejections, reported in real-time

• Custom Exceptions: Exceptions actively caught in business code can be manually reported through the SDK reporting interface, suitable for recording non-fatal errors or business logic exceptions

Long Task and ANR (Performance Issue)

Detects performance bottlenecks during application runtime.

Performance Issue Types

• ANR (Application Not Responding) - Mobile: Main thread unresponsive for an extended period, typically caused by deadlock, excessive synchronous I/O, or complex computation

• Frame Rate Drops - Mobile: Rendering frame rate falls below threshold, causing users to perceive UI lag

• Long Task: Tasks with execution time exceeding the threshold, detected on both web and mobile platforms

Investigating User Complaints

Scenario: A user reports "the page showed a blank screen after opening."

Solution: Use User Session Trace to locate the corresponding session by User ID or Device ID and examine the complete event sequence before and after the blank screen. Check whether page load time was abnormal, whether any resource requests failed, or whether JavaScript exceptions were triggered, enabling rapid root cause identification.

Analyzing Page Conversion Funnels

Scenario: Analyze the conversion path from homepage to checkout page.

Solution: Use the page navigation sequence in session traces to track user journey. Combined with time spent on each page and action events, identify where users drop off—whether due to slow page loads, interaction lag, or overly complex navigation flows.

Diagnosing Slow Request Impact

Scenario: An API endpoint becomes slow.

Solution: Use session traces to examine the complete experience of affected users. Determine which page the slow request occurred on, whether users repeatedly clicked while waiting, and whether they ultimately abandoned the application. Combined with phased timing data for resource requests (DNS, TCP, TTFB), determine whether the issue is network-related or server-side.